A family of long interspersed repetive DNA sequences in the human gerome has been characterized utilizing a member of the family present immediately 3' to the human Beta globin gene. 3000-4800 other members of this family are dispersed throughout the genome. In situ hybridization, using a portion of the member the repeat family adjacent to the Beta globin gene as a probe, has revealed that the family is represented more or less uniformly on all human chromosomes with no evidence of centromeric localization. The sequence homology of 3 members of the family has been defined precisely by DNA sequencing of the 5' end; one member precisely abuts another characterized repetitive DNA element, whereas other members of the 6.4 kb family are found in DNA which is not highly repetitive. A small portion of the member of the repeat found near the Beta globin gene appears to be weakly homologous to sequences found near the SV40 origin of replication. Experiments are in progress to determine whether there are enhancer-like elements, analogous to the 72 bp direct repeats in the SV40 genome, within individual members of the 6.4 kb repeat sequence family.